Necromancy of Thay: Open It and Continue in Act 3 · Campaign rules and dated source guidance
BG3 Necromancy of Thay: Open It and Continue in Act 3
Quick Answer
Find the Necromancy of Thay in the Blighted Village apothecary cellar, then insert the Dark Amethyst from the Whispering Depths to open it. Choose its reader carefully. The later reading stage requires The Tharchiate Codex in Act 3.
- Reading time
- 1 minutes
- Difficulty
- Focused guide
- Checked
- 2026-09-09
On this page
Guide details
Before you begin
Find the Necromancy of Thay and Dark Amethyst, choose a reader, continue with The Tharchiate Codex in Act 3, and weigh keeping the book against destroying it.
Focused campaign guidance; unrelated story, romance and complete-build routes are not covered.
- Status
- Sources checked
- Edition
- Campaign rules and dated source guidance
- Platform
- PC · Steam
- Checked
- 2026-09-09
- Check note
- Source dates and version limits are stated where relevant; no in-game playtest claimed.
Before you set out
Prerequisites#
- Focused campaign guidance; unrelated story, romance and complete-build routes are not covered.
Route 01
Find the book and its separate key#
Collect the book and Dark Amethyst#
The book is in the apothecary cellar beneath the Blighted Village. Its key is the Dark Amethyst in the Whispering Depths, near the Phase Spider Matriarch. Getting into the cellar and opening the book are different tasks: obtaining the book alone does not unlock its cover. Once you have the amethyst, examine the book in your inventory and use the option to insert it.
Route 02
Choose who will read it before committing#
Commit with the intended reader#
The book becomes bound to its reader. Its early reading can grant Speak with Dead and Forbidden Knowledge, so choose the character you intend to continue with. Ordinary dialogue presents progressively harder Wisdom checks, while class-specific choices can differ. Read the options your character actually receives. Do not assume that every reward requires every roll to succeed, or that another character will see identical checks.
Route 03
Read The Tharchiate Codex before returning to the book#
Use the Codex, then read again#
For the later stage, find and read The Tharchiate Codex in the Sorcerous Vault beneath Sorcerous Sundries in Act 3. Return to the Necromancy of Thay with its reader afterward to pursue Danse Macabre. Remove Curse can clear the Codex’s curse. If you are still in the earlier acts, the missing Codex prerequisite is not evidence that your save is broken.